diff --git a/src/add-ons/kernel/bus_managers/ata/ata.c b/src/add-ons/kernel/bus_managers/ata/ata.c
index 7a54624a8c..f2e722c9c4 100644
--- a/src/add-ons/kernel/bus_managers/ata/ata.c
+++ b/src/add-ons/kernel/bus_managers/ata/ata.c
@@ -18,6 +18,11 @@
 #define TRACE dprintf
 #define FLOW dprintf
 
+
+static void ata_exec_dma_transfer(ata_request *request);
+static void	ata_exec_pio_transfer(ata_request *request);
+
+
 void
 ata_select_device(ide_bus_info *bus, int device)
 {
@@ -29,16 +34,10 @@ ata_select_device(ide_bus_info *bus, int device)
 	tf.chs.mode = ide_mode_lba;
 	tf.chs.device = device ? 1 : 0;
 
-//	if (ata_wait_idle(bus) != B_OK)
-//		FLOW("ata_select_device step 1 bus not idle\n");
-
 	bus->controller->write_command_block_regs(bus->channel_cookie, &tf, ide_mask_device_head);
 	bus->controller->get_altstatus(bus->channel_cookie); // flush posted writes
 	spin(1); // wait 400 nsec
 
-//	if (ata_wait_idle(bus) != B_OK)
-//		FLOW("ata_select_device step 2 bus not idle\n");
-
 	// for debugging only
 	bus->controller->read_command_block_regs(bus->channel_cookie, &tf, ide_mask_device_head);
 	if (tf.chs.device != device)
@@ -756,7 +755,7 @@ err:
 
 void
 ata_exec_read_write(ide_device_info *device, ata_request *request,
-	uint64 pos, size_t length, bool write)
+	uint64 address, size_t sectorCount, bool write)
 {
 	ide_bus_info *bus = device->bus;
 	ata_flags flags = 0;
@@ -769,19 +768,18 @@ ata_exec_read_write(ide_device_info *device, ata_request *request,
 	if (request->uses_dma) {
 		if (!prepare_dma(device, request)) {
 			// fall back to PIO on error
-
 			request->uses_dma = false;
 		}
 	}
 
 	if (!request->uses_dma) {
 		prep_PIO_transfer(device, request);
-		device->left_blocks = length;
+		device->left_blocks = sectorCount;
 	}
 
 	// compose command
-	if (!create_rw_taskfile(device, request, pos, length, write))
-		goto err_setup;
+	if (!create_rw_taskfile(device, request, address, sectorCount, write))
+		goto error;
 
 	// if no timeout is specified, use standard
 	timeout = request->ccb->timeout > 0 ? request->ccb->timeout * 1000 : IDE_STD_TIMEOUT;
@@ -791,42 +789,80 @@ ata_exec_read_write(ide_device_info *device, ata_request *request,
 	if (request->uses_dma)
 		flags |= ATA_DMA_TRANSFER;
 	if (ata_send_command(device, request, flags, timeout) != B_OK) 
-		goto err_send;
+		goto error;
 
+	// this could be executed in a DPC to improve performance
 	if (request->uses_dma) {
-
-		start_dma_wait_no_lock(device, request);
+		ata_exec_dma_transfer(request);
 	} else {
-		// on PIO read, we start with waiting, on PIO write we can
-		// transmit data immediately; we let the service thread do
-		// the writing, so the caller can issue the next command 
-		// immediately (this optimisation really pays on SMP systems
-		// only)
-		SHOW_FLOW0(3, "Ready for PIO");
-		if (request->is_write) {
-			SHOW_FLOW0(3, "Scheduling write DPC");
-			scsi->schedule_dpc(bus->scsi_cookie, bus->irq_dpc, ide_dpc, bus);
-		}
+		ata_exec_pio_transfer(request);
+	}
+	return;
+
+error:
+	if (request->uses_dma)
+		abort_dma(device, request);
+	ata_request_finish(request, false);
+}
+
+
+static void
+ata_exec_dma_transfer(ata_request *request)
+{
+	ASSERT(0);
+}
+
+static void
+ata_exec_pio_transfer(ata_request *request)
+{
+	ide_device_info *device = request->device;
+	ide_bus_info *bus = device->bus;
+	uint32 timeout = request->ccb->timeout > 0 ? 
+		request->ccb->timeout * 1000 : IDE_STD_TIMEOUT;
+
+//	FLOW("ata_exec_pio_transfer\n");
+
+	FLOW("ata_exec_pio_transfer: length %d, left_sg_elem %d, cur_sg_elem %d, cur_sg_ofs %d\n",
+		request->ccb->data_length, device->left_sg_elem, device->cur_sg_elem, device->cur_sg_ofs);
+
+	if (ata_wait(bus, ide_status_drq, ide_status_bsy, 0, 4000000) != B_OK) {
+		TRACE("ata_exec_pio_transfer: wait failed\n");
+		goto error;
 	}
 
+	while (device->left_blocks > 0) {
+		if (request->is_write) {
+			FLOW("writing 1 block\n");
+			if (write_PIO_block(request, 512) != B_OK)
+				goto transfer_error;
+		} else {
+			FLOW("reading 1 block\n");
+			if (read_PIO_block(request, 512) != B_OK)
+				goto transfer_error;
+		}
+		device->left_blocks--;
+		FLOW("%d blocks left\n", device->left_blocks);
+	}
+
+	if (ata_wait_for_drqdown(bus) != B_OK) {
+		TRACE("ata_exec_pio_transfer: ata_wait_for_drqdown failed\n");
+		goto error;
+	}
+
+	ata_finish_command(device, &request, ATA_WAIT_FINISH | ATA_DRDY_REQUIRED, ide_error_abrt);
+	ata_request_finish(request, false /* resubmit */);
 	return;
 
-err_setup:
-	// error during setup
-	if (request->uses_dma)
-		abort_dma(device, request);
-
-	ata_request_finish(request, false);
+error:
+	TRACE("ata_exec_pio_transfer: error\n");
+	ata_request_set_status(request, SCSI_SEQUENCE_FAIL);
+	ata_request_finish(request, false /* resubmit */);
 	return;
-	
-err_send:
-	// error during/after send; 
-	// in this case, the device discards queued ccb automatically
-	if (request->uses_dma)
-		abort_dma(device, request);
 
-//	finish_reset_queue(request);
-	ata_request_finish(request, false);
+transfer_error:
+	TRACE("ata_exec_pio_transfer: transfer error\n");
+	ata_request_set_status(request, SCSI_SEQUENCE_FAIL);
+	ata_request_finish(request, false /* resubmit */);
 }
 
 
@@ -1079,7 +1115,7 @@ ata_identify_device(ide_device_info *device, bool isAtapi)
 		return B_ERROR;
 	}
 
-	if (ata_wait(bus, ide_status_drq, ide_status_bsy, ATA_CHECK_ERROR_BIT, 4000000) != B_OK) {
+	if (ata_wait(bus, ide_status_drq, ide_status_bsy, 0, 4000000) != B_OK) {
 		TRACE("ata_identify_device: wait failed\n");
 		return B_ERROR;
 	}
diff --git a/src/add-ons/kernel/bus_managers/ata/ata_request.c b/src/add-ons/kernel/bus_managers/ata/ata_request.c
index b6812abc49..71b558b674 100644
--- a/src/add-ons/kernel/bus_managers/ata/ata_request.c
+++ b/src/add-ons/kernel/bus_managers/ata/ata_request.c
@@ -139,7 +139,7 @@ ata_request_finish(ata_request *request, bool resubmit)
 	}
 
 	IDE_LOCK(request->device->bus);
-	ASSERT(request->device->bus->state == ata_state_busy);
+	ASSERT(request->device->bus->state != ata_state_idle);
 	ASSERT(request->device->bus->active_device == request->device);
 	ASSERT(request->device->requestActive == request);
 	ASSERT(request->device->requestFree == NULL);
diff --git a/src/add-ons/kernel/bus_managers/ata/ide_internal.h b/src/add-ons/kernel/bus_managers/ata/ide_internal.h
index 136661ae38..018ad314e7 100644
--- a/src/add-ons/kernel/bus_managers/ata/ide_internal.h
+++ b/src/add-ons/kernel/bus_managers/ata/ide_internal.h
@@ -208,7 +208,7 @@ status_t ata_finish_command(ide_device_info *device, ata_request *request, ata_f
 bool check_rw_error(ide_device_info *device, ata_request *request);
 bool check_output(ide_device_info *device, bool drdy_required, int error_mask, bool is_write);
 
-void ata_exec_read_write(ide_device_info *device, ata_request *request,	uint64 pos, size_t length, bool write);
+void ata_exec_read_write(ide_device_info *device, ata_request *request, uint64 address, size_t sectorCount, bool write);
 
 void ata_dpc_DMA(ata_request *request);
 void ata_dpc_PIO(ata_request *request);
diff --git a/src/add-ons/kernel/bus_managers/ata/pio.c b/src/add-ons/kernel/bus_managers/ata/pio.c
index fb36bb1d84..132eb88816 100644
--- a/src/add-ons/kernel/bus_managers/ata/pio.c
+++ b/src/add-ons/kernel/bus_managers/ata/pio.c
@@ -43,6 +43,7 @@
 
 #include <string.h>
 
+#define FLOW dprintf
 
 // internal error code if scatter gather table is too short
 #define ERR_TOO_BIG	(B_ERRORS_END + 1)
@@ -157,6 +158,8 @@ transfer_PIO_physcont(ide_device_info *device, addr_t physicalAddress,
 			return B_ERROR;
 		}
 
+		ASSERT((physicalAddress & 4097) == (virtualAddress & 4097));
+
 		// if chunks starts in the middle of a page, we have even less then
 		// a page left		
 		page_left = B_PAGE_SIZE - physicalAddress % B_PAGE_SIZE;
@@ -184,7 +187,7 @@ transfer_PIO_physcont(ide_device_info *device, addr_t physicalAddress,
 
 
 /*! Transfer PIO block from/to buffer */
-static inline int
+static inline status_t
 transfer_PIO_block(ide_device_info *device, int length, bool write, int *transferred)
 {
 	// data is usually split up into multiple scatter/gather blocks
@@ -230,10 +233,8 @@ transfer_PIO_block(ide_device_info *device, int length, bool write, int *transfe
 static void
 write_discard_PIO(ide_device_info *device, int length)
 {
+	static const uint8 buffer[32] = {};
 	ide_bus_info *bus = device->bus;
-	uint8 buffer[32];
-
-	memset(buffer, 0, sizeof(buffer));
 
 	// we transmit 32 zero-bytes at once
 	// (not very efficient but easy to implement - you get what you deserve